In Windows and OSX, the builtin software is not stuff we can influence. When Apple decides to use another soundserver that is what happens. There are no different expectations. Linux is a different beast.
Take me as example. I just got burned often enough by pulseaudio that I really don't want to try it again. When it was introduced there were countless support threads in the linux forum I frequented at the time with broken systems, and also my own did only work when I reverted to ALSA. Also later, when everything was supposed to work, PA just did not work for me. Yes, I'm using it by now on my laptop, but it's not like that is a flawless experience – and I highly assume PA is at least partly responsible for the issues with the sound system on there.
Now, it's not only pulseaudio. See what the Gentoo wiki writes (https://wiki.gentoo.org/wiki/PulseAudio):
> This is the only supported configuration by upstream and Gentoo developers.
> PulseAudio uses udev and ConsoleKit to dynamically give access to the soundcards to the currently "active" nr. When running Systemd this will be handled without needing ConsoleKit.
ConeoleKit is unmaintained and to my understanding bloat that is just completely unnecessary, especially on my single user desktop system. And of course systemd won't come on my main system, I completely oppose it. Relying on PA means moving into the wrong part of Linux.
Maybe it won't be a big problem in the end, with the ALSA code still being available. Still, not a good thing, and in my eyes indeed a development decision one can complain about.